The overall issue of assessment during early childhood, and its relation to school readiness and other decisions, is currently widely debated. Expanding early childhood education/child care enrollments, better scientific knowledge about early childhood development, and decisions about public spending, all oblige persons working with young children, and their parents, to carefully consider which assessment tools to use, as well as why and when to use them. We need to utilize assessments that yield the most-needed, developmentally grounded information, most economically and most ethically in terms of teacher, parent, and child time, effort, and attention. In particular, better social and emotional assessment tools are sorely needed. The disconnection between the importance of the social and emotional domains of development and their status within educational programming and assessment has long been lamented (Denham, Lydick, Mitchell-Copeland, &Sawyer, 1996). In what appears to be ever-broadening recognition, however, the last several years have witnessed a blossoming of attention to these areas during early childhood, as crucial for both concurrent and later well-being and mental health, as well as learning and academic success. Further, Head Start programs cite emotional-behavior issues among their top needs for training and technical assistance. Similarly, teachers view children's "readiness to learn" and "teachability" as marked by positive emotional expressiveness, enthusiasm, and ability to regulate emotions and behaviors . Based on these assertions, we propose to refine and test a battery of preschool social-emotional outcome measures, which tap several constructs central to emotional and social competence theory, specifically emotional expression, emotion regulation, emotion knowledge, social problem solving, and positive and negative social behavior. The overall five-year plan includes piloting of current versions of selected assessment tools, large scale administration and revision of each, as well as psychometric evaluation, initial norming, and examination of the measures'abilities to demonstrate program effects and usefulness in understanding individual children.